Wind power is intermittent making it difficult for the grid to accept its power. The output from a wind farm is usually to pass through an electronic filter to regulate the voltage and frequency etc. before it is uploaded. A general rule is that the wind power cannot exceed 20-23% of the base load power; otherwise the unsteady output from the wind power will cause the grid to be overloaded and shut down. An energy storage unit which can store wind energy up to long hours such as 24 hours would help to relax or eliminate the restriction of the wind energy to be uploaded to the grid, since the regenerated power from the storage is stable and in good quality ready for upload.
The present methods for deep water wind turbine foundation are mainly those borrowed from offshore oil industry which uses either steel tubes as piles or concrete caisson foundation resting on the seabed. Floating wind turbines have been suggested and tested but the isolated floating turbines are easily affected by the surface wave. The piles/caisson foundation for the much lighter wind turbines would end up with an out-of-proportion foundation cost compared with the much heavier offshore oil drilling platform. The large number of turbines in a wind farm also makes this type of foundation impracticable for deep water applications.
The present patent application addresses these two major concerns: deep water foundation and intermittent nature of renewable energy, and resolves them with floating raft base incorporated with energy storage facility.